Fiber‐Level Modeling of In‐Plane Shear Behavior for 3D Braided Composites Based on the Material Twin Models

This study presents an integrated experimental and numerical approach to investigate the in‐plane shear properties of three‐dimensional (3D) braided composites. A novel methodology integrates high‐fidelity modeling techniques (including virtual braiding, virtual fiber embedded (VFE), and stiffness correction) into a unified digital twin framework, enabling full‐scale material twin modeling of 3D braided composites. Damage models for matrix and fibers were established to model the failure process of the material twin model. In‐plane shear tests of composite specimens were conducted, where the full‐field strain distribution of the specimens and the failure modes of internal microstructures were obtained using DIC (Digital Image Correlation) and Micro‐CT (Micro‐Computed Tomography) tests, respectively. Experimental validation revealed strong agreement between simulation and test results. A systematic quantitative analysis of process‐structure‐mechanics relationships was performed using the material twinning concept. This study provides valuable guidance for the parameter design of 3D braided composites and can be extended to the structural design of other types of textile composites.